Liquid metal high pressure pump



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LIQUID METAL HIGH PRESSURE PUMP Filed Jan. 16, 1953 2 Sheets-Sheet 1 FIG. I.

a C v L/QU/O METAL I RES/STANCE A A A A A I I WALL RES/STANCE INVENTOR LEON/4P0 5. MA/DEA/EE/PG BY I ATTORNEY Sept. 6, 1955 B. VANDENBERG 2,716,943

LIQUID METAL HIGH PRESSURE PUMP Filed Jan. 16, 1953 2 sheets-Sheet 2 FIG. 3.

PR55UR Ki r0774; CURRENT EQUATION UFL/NE Pa =.00/ I I? PIPEZiU/PE P57 MILL/VOLTS v5. 1;

1; 7074!. CURRENT I NVENTOR 1E O/VHED 5. VA/VOE/VBERG ATTORNEY United States Patent LIQUID METAL HIGH PRESSURE PUMP Leonard V. Vandenberg, Sharon Springs, N. Y., assignor to the United States of America as represented by the United States Atomic Energy Commission Application January 16, 1953, Serial No. 331,653

3 Claims. (Cl. 103-1) in many cases, simplify the design and maintenance of 2 such devices.

Conventional hydraulic systems have developed gear, screw and positive displacement pumps for the production of high heads and low flows which find applications in control systems and hydraulic transmission of torque n u) and linear movement.

It is the principal object of this invention to provide an electromagnetic liquid metal pump capable of economically producing such high heads and low flows.

It is a further object of this invention to provide an electromagnetic pump in which the ratio of amperes to pressure output is small compared with that obtainable with conventional electromagnetic pumps so that inexpensive power supplies may be utilized.

The foregoing objects are attained by creating am l, magnetic field either by use of permanent magnets or by 40 causi-ngan electric current to flow through a series of coils arranged to create a radial magnetic field in the body of the pump. After passing through the coils, the current enters the inlet for the liquid metal pump and furnishes the armature current therefor. As a result of interaction between the current in the liquid metal and the radial magnetic field set up by the coils, the liquid metal is caused to flow in a spiral path through the pump, each turn of the spiral acting as a pump in series 7' with pumps formed by preceding spirals. The total force or pressure output is a product of the number of spiral or convolutions times the force or pressure contributed by each of such spirals. Preferably direct current is used.

The invention may be more fully understood by reference to the figures, wherein:

Fig. 1 is a schematic circuit diagram of the pumps; and

Fig. 2 is a cross sectional view of a pump, constructed H in accordance with this invention, and

Fig. 3 is a graph of test data obtained with a pump constructed according to this invention and showing the relationship of pressure to total current, and of voltage to total current.

The basic circuit diagram of the pump appears in Fig. 1. It consists of a power supply. which may be D. C., as shown, or A. C. The circuit includes a pair of coils in series with each other and with parallel resistances symbolizing the equivalent armature resistance, of the liquid metal in the pump and the wall resistance of the fluid channel tubing for the liquid metal. Counter 2,716,943 Patented Sept. 6, 1955 ice . electromotive force induced in the fluid due to its velocity in the field is represented by the symbol G.

In the embodiment of the invention shown in Fig. 2, the pump comprises a cylinrdical housing which supports a pair of magnetizable cores 11, 12 axially thereof. The latter are spaced a short distance apart to establish an air gap 13 therebetween at the central section of the pump and form poles for a radial magnetic field as shown by the dotted lines in Fig. 2.

A conductor 14, connectable with a suitable source of alternating or direct current (not shown) enters the pump housing through an aperture 15 adjacent one end thereof and is wound around the core 11 to form a coil 16. The conductor is then wound in the reverse direction, around core 12 to form a second coil 17, after which it emerges through aperture 18 and is electrically connected with the inlet conduit 19 of the pump. When a current flows through the conductor 14, the circuit is completed by passing through the pump and a return conductor 20, electrically connected with the pump outlet pipe 21. Thus the current which enters the pump through conductor 14, supplies both the energy for the magnetomotive force developed in the cores 11, 12 and also the armature current for the liquid metal in the pump.

In the embodiment shown in Fig. 2, each of the coils 16, 17 consists of 10.8 turns. The cores 11, 12 are of iron, forming a pair of electromagnets which provides the source of magnetomotive force for operation of the pump. A split iron collar 22 coaxial of the core ends, and sections of cylindrical iron pipe 23, 24 complete the magnetic circuit. The magnetic lines enter the pump from each end and extend radially to the iron collar whence the flux completes the circuit through the iron pipe as indicated by dotted lines in Fig. 2. 1n the alternative, cores 11, 12 may consist of Alnico permanent magnets, in which case the coils 16, 17 may be eliminated.

The pumping section comprises an annulus coaxial E of and intermediate the split iron collar 22 and the ends 25, 26 of the cores 11, 12. Pins 27 threaded on the inner wall 28 of the pump annulus define channels that direct the liquid metal in a spiral path as it proceeds from the inlet 19 to the outlet 21. In the example shown in Fig. 2 the fins divide the pumps annulus into channels /s" by A" in cross section, and completing twenty turns. The outer wall 29 is a shrink fit over the fins.

In operation, current fiowing through the conductor 14, and coils 16, 17 sets up a radial magnetic field. The

current then enters the liquid metal and forms the armature current for the pump. The interaction of the armature current with the radial magnetic field creates a force on the liquid metal in the same direction as the spiral path formed by the fins in the pump annulus. Each convolution acts as a pump in series with pumps formed by preceding convolutions. The total force or pressure output is the product of the number of convolutions times the force or pressure contribution of each convolution.

Fig. 3 is a graph of performance of a liquid metal pump constructed according to this invention and illustrates the relation between pressure output of the pump at no fiow and the total current, It. It passes through both coils but divides into IL and Ia. at the pump armature. Ia is the actual armature current. The last point on the curve is at 29 p. s. i., since the gages used in the test would not permit measurement of higher pressures. The pressure varies as It until the iron becomes saturated, and then it varies as the first power as It, which forms a line on the graph. The limitations to the maximum pressure obtainable is the armature temperature rise caused by It R losses and stress in the pump from fluid pressure.

The present invention provides a pump in which high pressures are obtainable from small power supplies. For example, the described pump produces pressures of 30 p. s. i. with 15 watts of power absorbed by the pump. With such a pump it is practical to use storage batteries for a D. C. supply. A. C. power may be obtained from a small current transformer.

I claim:

1. A high pressure electromagnetic pump for liquid conductors comprising a pump inlet and outlet, an an: nular pumping chamber communicating with the inlet and outlet, finsflividing the chamber into a plurality of spiral channels, means for passing an armature current through the liquid conductor, and a pair of electromagnets arranged in spaced end to end relationship, said electromagnets being connected in series with each ther and in series with the armature current, said electromagnets being arranged to establish a radial magnetic field and positioned to interact with the armature current whereby a pressure is created on the liquid conductor in the direction of the spiral channels.

2. A high pressure electromagnetic pump for liquid conductors comprising a pump inlet and outlet, an annular pumping chamber communicating with the inlet and outlet, fins dividing the chamber into a plurality of spiral channels, a collar of magnetically permeable material coaxial of and surrounding the pumping chamber, means for passing an armature current through the liquid conductor, and a pair of reversely wound electromagnets arranged in spaced end to end relationship, said electromagnets being connected in series with each other and in series with the armature current, said electromagnets being arranged coaxially of both the annular chamber and the collar whereby a radial magnetic field is established in a position to interact with the armature current to create a pressure on the liquid conductor in the direction of the spiral channels.

3. A high pressure electromagnetic pump for liquid conductors comprising a cylindrical housing, a pair of cores in spaced end to end relationship within the housing, a pumping chamber arranged coaxially around the cores and divided by fins into a plurality of spiral channels, a magnetically permeable collar arranged around the chamber and coaxial of both the chamber and the cores, a pump inlet and outlet communicating with the chamber, and a conductor wound around each of the cores, the direction of winding on one of the cores being the reverse of the direction of winding on the other core, said conductor being electrically connected with the pump inlet to provide an armature current in series with the core windings, whereby a current in the conductor will create both a radial magnetic field across the annular chamber and an armature current to interact therewith and create a force in the direction of the spiral channels.

References Cited in the file of this patent UNITED STATES PATENTS 1,298,664 Chubb Apr. 1, 1919 2,317,166 Abrams Apr. 20, 1943 2,386,369 Thompson Oct. 9, 1945 2,397,785 Friedlander Apr. 2, 1946 2,558,698 Wade June 26, 1951 2,612,109 Wakefield Sept. 30, 1952 2,655,107 Godbold Oct. 13, 1953 2,658,452 Donelian Nov. 10, 1953 FOREIGN PATENTS 239,816 Switzerland Mar. 1, 1946 511,137 Germany Oct. 27, 1930 

1. A HIGH PRESSURE ELETROMAGNETIC PUMP FOR LIQUID CONDUCTORS COMPRISING A PUMP INLET AND OUTLET, AN ANNULAR PUMP CHAMBER COMMUNICATING WITH THE INLET AND OUTLET, FINS DIVIDING THE CHAMBER INTO A PLURALITY OF SPIRAL CHANNELS, MEANS FOR PASSING AND ARMATURE CURRENT THROUGH THE LIQUID CONDUCTOR, AND A PAIR OF ELECTROMAGNETS ARRANGED IN SPACED END TO END RELATIONSHIP, SAID ELECTROMAGNETS BEING CONNECTED IN SERIES WITH EACH OTHER AND IN SERIES WITH THE ARMATURE CURRENT, SAID ELECTROMAGNETS BEING ARRANGED TO ESTABLISH A RADIAL MAGNETIC FIELD AND POSITIONED TO INTERACT WITH THE ARMATURE CURRENT WHEREBY A PRESSURE IS CREATED ON THE LIQUID CONDUCTOR IN THE DIRECTION OF THE SPIRAL CHANNELS. 